export default {
	namespaced: true,

	state: () => ({
		// 购物车的数组，用来存储购物车中每个商品的信息对象
		// 每个商品的信息对象，都包含如下 6 个属性：
		// { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
		cart: JSON.parse(uni.getStorageSync('cart') || '[]'),
	}),
	mutations: {
		addToCart(state, goods){
			const findResult = state.cart.find(item => item.goods_id === goods.goods_id)
			if(!findResult){
				state.cart.push(goods)
			} else {
				findResult.goods_count++
			}
			// 这种写法真是难理解，调用m_cart模块下的saveToStorage方法
			this.commit('m_cart/saveToStorage')
		},
		saveToStorage(state){
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		// 更新购物车中商品的选中状态
		updateGoodsState(state, goods){
			const findResult = state.cart.find(item => item.goods_id === goods.goods_id)
			if(findResult){
				findResult.goods_state = goods.goods_state
				this.commit('m_cart/saveToStorage')
			}
		},
		// 更新购物车中商品的数量
		updateGoodsCount(state, goods){
			const findResult = state.cart.find(item => item.goods_id === goods.goods_id)
			if(findResult){
				findResult.goods_count = goods.goods_count
				this.commit('m_cart/saveToStorage')
			}
		},
		// 根据商品id删除购物车中某件商品
		removeGoodsById(state, goods_id){
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)
			this.commit('m_cart/saveToStorage')
		},
		// 更新购物车中权限radio的选中状态
		updateAllGoodsState(state, newState){
			state.cart.forEach(item => item.goods_state = newState)
			this.commit('m_cart', 'saveToStorage')
		}
		
	},
	getters: {
		total(state){
			// let c = 0
			// state.cart.forEach(goods => c += goods.goods_count)
			// return c
			return state.cart.reduce((total, item) => total += item.goods_count, 0)
		},
		checkedCount(state){
			return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
		},
		// 计算已勾选商品总价
		checkedGoodsAmount(state){
			const checkedGoods = state.cart.filter(item => item.goods_state)
			const res = checkedGoods.reduce((total, item) => total += item.goods_count * item.goods_price, 0).toFixed(2)
			return res
		}
	}
}